Spatial Patterns and Cross‐Correlations of Temporal Changes in Soil Carbonates and Surface Elevation in a Winter Wheat–Fallow Cropping System
Spatial Patterns and Cross‐Correlations of Temporal Changes in Soil Carbonates and Surface Elevation in a Winter Wheat–Fallow Cropping System
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冬小麦-休耕制度土壤碳酸盐和地表高程的时间变化的空间格局和互相关性
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发表时间：
2015
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通讯作者：
T. Green
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作者：
L. Sherrod;R. Erskine;T. Green
土壤侵蚀和沉积影响美国半干旱大平原农田的可持续性。高分辨率数字高程图之间的时间差异提供了空间侵蚀或沉积的物理估计，而钙层的深度是一个化学指标。我们假设土壤表层 CaCO₃ 浓度与地表高程 (Δz) 的变化呈负相关。我们研究了科罗拉多州东北部一片 109 公顷的冬小麦田（Triticum aestivum L.）——垂直于盛行风的交替条带休耕轮作。使用改进的压力钙计方法对 2001 年和 2012 年从 185 个景观位置收集的土壤样本（顶部 30 厘米）进行了 CaCO₃ 分析。 CaCO₃ (ΔC) 的变化与大规模侵蚀和沉积区域（分别为西块和东块）以及土壤单元显着相关，而 Δz 与管理带和块相关。西地块的平均ΔC为3.2 g kg-1，侵蚀量为2.0 cm，而东地块的平均ΔC降低了4.4 g kg-1，沉积量为4.2 cm。山顶位置的 CaCO₃ 最高，坡脚位置的 CaCO₃ 最低。我们发现两个侵蚀区域（Δz 5 cm）的山顶和坡脚位置的 Δz 和 ΔC 之间存在反比关系，但总体而言 Δz 与 ΔC 没有显着相关。 CaCO₃ 的高值（>100 g kg⁻1）随着时间的推移而降低。高分辨率的 Δz 地图显示了跨尺度的复杂空间模式，这推断出水和风的侵蚀和沉积受到地形和管理的影响。
Soil erosion and deposition impact the sustainability of agricultural lands within the semiarid Great Plains in the United States. Temporal differences between high-resolution digital elevation maps provide physical estimates of spatial erosion or deposition, and the depth to a calcic horizon is a chemical indicator. We hypothesized that soil surface layer CaCO₃ concentration is inversely correlated with the change in surface elevation (Δz). We studied a 109-ha field in northeastern Colorado under winter wheat (Triticum aestivum L.)–fallow rotation in alternating strips perpendicular to the prevailing wind. Soil samples (top 30 cm) collected from 185 landscape positions in 2001 and 2012 were analyzed for CaCO₃ using a modified pressure-calcimeter method. The change in CaCO₃ (ΔC) was significantly correlated with large-scale erosional and depositional areas (west and east blocks, respectively) and with soil units, whereas Δz was correlated with management strips and blocks. The west block had an average ΔC of 3.2 g kg⁻¹ with 2.0 cm of erosion, whereas the east block decreased by 4.4 g kg⁻¹ with 4.2 cm of deposition. Summit positions had the highest CaCO₃, and toeslope positions had the lowest. We found inverse relationships between Δz and ΔC in summit and toeslope positions at both erosional (Δz 5 cm) areas, but Δz was not correlated significantly with ΔC overall. High values of CaCO₃ (>100 g kg⁻¹) decreased with time. A high-resolution map of Δz showed complex spatial patterns across scales, which inferred water and wind erosion and deposition affected by terrain and management.